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    <title>Document</title>
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    <script>
        /******************简单类型****************/
        //string
        var str = '这是字符串';
        console.log(typeof str);//string
        //number
        var num = 20;
        console.log(typeof num);//number
        //布尔
        var bool = true;
        console.log(typeof bool);//boolean
        //undefined
        var a;
        console.log(typeof a);//undefined
        var b = null;
        console.log(typeof b);//unll | object
        

        /******************复杂数据类型****************/
        //对象
        var obj = {
            name:'老周',
            sayHi:function() {
                console.log('hi');    
            }
        }
        console.log(typeof obj);//object
        obj.sayHi();
        
        //数组
        var arr = [1,24,30];
        console.log(typeof arr);//object

        //date 时间对象
        var date = new Date();
        console.log(typeof date);//object

        var fun = function() {           
        }
        console.log(typeof fun);//function
        
        //结论：复杂数据类型 通过操作符 typeof 操作得到 的类型为 object;
        //但是function 这个复杂数据类型除外，它得到的类型为 function;
        
        //简单数据类型的包装
        var str1 = str.substr(1);
        console.log(str1);
        
    </script>
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